estate and probate law, is estate responsible for credit card and other debt of decedent

Whoever is named as the debtor on the credit card agreement is liable. If that is only the deceased spouse, then that person's estate is liable. In the 10 community property states (like California and Arizona), both spouses are probably liable. The probate statutes in most states encourage people like you to hire an attorney to help you through this type of situation. The reason is that professional services and other expenses of administration are usually paid (according to the statute) prior to other expenses (even the IRS). So, if you have $10,000 of credit card debt, and only $2,000 in a bank account, you might as well spend the money to hire an attorney to try to deal with the creditors for you. That attorney can help negotiate a settlement with the creditors and generally help you get back on your feet. Good luck.

By the way, I practice only in Arizona. Be sure to contact a local attorney.